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29 #include "AudioResampler.h"
33 #include <wtf/MathExtras.h>
39 const double AudioResampler::MaxRate = 8.0;
41 AudioResampler::AudioResampler()
44 m_kernels.append(adoptPtr(new AudioResamplerKernel(this)));
45 m_sourceBus = adoptPtr(new AudioBus(1, 0, false));
48 AudioResampler::AudioResampler(unsigned numberOfChannels)
51 for (unsigned i = 0; i < numberOfChannels; ++i)
52 m_kernels.append(adoptPtr(new AudioResamplerKernel(this)));
54 m_sourceBus = adoptPtr(new AudioBus(numberOfChannels, 0, false));
57 void AudioResampler::configureChannels(unsigned numberOfChannels)
59 unsigned currentSize = m_kernels.size();
60 if (numberOfChannels == currentSize)
61 return; // already setup
63 // First deal with adding or removing kernels.
64 if (numberOfChannels > currentSize) {
65 for (unsigned i = currentSize; i < numberOfChannels; ++i)
66 m_kernels.append(adoptPtr(new AudioResamplerKernel(this)));
68 m_kernels.resize(numberOfChannels);
70 // Reconfigure our source bus to the new channel size.
71 m_sourceBus = adoptPtr(new AudioBus(numberOfChannels, 0, false));
74 void AudioResampler::process(AudioSourceProvider* provider, AudioBus* destinationBus, size_t framesToProcess)
80 unsigned numberOfChannels = m_kernels.size();
82 // Make sure our configuration matches the bus we're rendering to.
83 bool channelsMatch = (destinationBus && destinationBus->numberOfChannels() == numberOfChannels);
84 ASSERT(channelsMatch);
88 // Setup the source bus.
89 for (unsigned i = 0; i < numberOfChannels; ++i) {
90 // Figure out how many frames we need to get from the provider, and a pointer to the buffer.
92 float* fillPointer = m_kernels[i]->getSourcePointer(framesToProcess, &framesNeeded);
97 m_sourceBus->setChannelMemory(i, fillPointer, framesNeeded);
100 // Ask the provider to supply the desired number of source frames.
101 provider->provideInput(m_sourceBus.get(), m_sourceBus->length());
103 // Now that we have the source data, resample each channel into the destination bus.
104 // FIXME: optimize for the common stereo case where it's faster to process both left/right channels in the same inner loop.
105 for (unsigned i = 0; i < numberOfChannels; ++i) {
106 float* destination = destinationBus->channel(i)->data();
107 m_kernels[i]->process(destination, framesToProcess);
111 void AudioResampler::setRate(double rate)
113 if (isnan(rate) || isinf(rate) || rate <= 0.0)
116 m_rate = min(AudioResampler::MaxRate, rate);
119 void AudioResampler::reset()
121 unsigned numberOfChannels = m_kernels.size();
122 for (unsigned i = 0; i < numberOfChannels; ++i)
123 m_kernels[i]->reset();
126 } // namespace WebCore
128 #endif // ENABLE(WEB_AUDIO)